Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Gond Gate

Gates you control enter untapped.
{T}: Add {C}.
{T}: Add one mana of any color that a Gate you control could produce.

Spire Garden

Spire Garden enters tapped unless you have two or more opponents.
{T}: Add {R} or {G}.

Swamp

White Dragon

Flying
Cold Breath — When White Dragon enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

True Polymorph

Target artifact or creature becomes a copy of another target artifact or creature.

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Explore the Underdark

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.
You take the initiative.

Thrakkus the Butcher

Trample
Whenever Thrakkus the Butcher attacks, double the power of each Dragon you control until end of turn.

Myrkul's Edict

Roll a d20.
1—9 | Choose an opponent. That player sacrifices a creature.
10—19 | Each opponent sacrifices a creature.
20 | Each opponent sacrifices a creature with the greatest power among creatures that player controls.

Stoneskin

Flash
Enchant creature
Enchanted creature gets +0/+10.

Luxury Suite

Luxury Suite enters tapped unless you have two or more opponents.
{T}: Add {B} or {R}.

Patron of the Arts

When Patron of the Arts enters or dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Tiamat

Flying
When Tiamat enters, if you cast it, search your library for up to five Dragon cards not named Tiamat that each have different names, reveal them, put them into your hand, then shuffle.

Run Away Together

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

Earthquake Dragon

This spell costs {X} less to cast, where X is the total mana value of Dragons you control.
Flying, trample
{2}{G}, Sacrifice a land: Return Earthquake Dragon from your graveyard to your hand.

Lozhan, Dragons' Legacy

Flying
Whenever you cast an Adventure or Dragon spell, Lozhan, Dragons' Legacy deals damage equal to that spell's mana value to any target that isn't a commander.

Manor Gate

Manor Gate enters tapped.
As Manor Gate enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Sand Augury

Scry 1, then draw a card. (Then exile this card. You may cast the creature later from exile.)

Young Blue Dragon

Young Blue Dragon // Sand Augury

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Charmed Sleep

Enchant creature
When Charmed Sleep enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Lurking Green Dragon

Flying
Lurking Green Dragon can't attack unless defending player controls a creature with flying.

Farideh's Fireball

Farideh's Fireball deals 5 damage to target creature or planeswalker. Roll a d20.
1—9 | Farideh's Fireball deals 2 damage to each player.
10—20 | Farideh's Fireball deals 2 damage to each opponent.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Guiding Bolt

Destroy target creature with power 4 or greater.
Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Klauth, Unrivaled Ancient

Flying, haste
Whenever Klauth, Unrivaled Ancient attacks, add X mana in any combination of colors, where X is the total power of attacking creatures. Spend this mana only to cast spells. Until end of turn, you don't lose this mana as steps and phases end.

Thunderwave

Roll a d20.
1—9 | Thunderwave deals 3 damage to each creature.
10—19 | You may choose a creature. Thunderwave deals 3 damage to each creature not chosen this way.
20 | Thunderwave deals 6 damage to each creature your opponents control.

Call to the Void

Each player secretly chooses a creature they control and a creature they don't control. Then those choices are revealed. Destroy each creature chosen this way.

Stunning Strike

Flash
Enchant creature
When Stunning Strike enters, tap enchanted creature and remove it from combat.
As long as enchanted creature isn't legendary, it doesn't untap during its controller's untap step.

Demogorgon's Clutches

Target opponent discards two cards, mills two cards, and loses 2 life. (To mill a card, a player puts the top card of their library into their graveyard.)

Plains

Eldritch Pact

Target player draws X cards and loses X life, where X is the number of cards in their graveyard.

Rob the Hoard

Return target artifact, enchantment, or legendary card from your graveyard to your hand. (Then exile this card. You may cast the creature later from exile.)

Crystal Dragon

Crystal Dragon // Rob the Hoard

Manifold Key

{1}, {T}: Untap another target artifact.
{3}, {T}: Target creature can't be blocked this turn.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Entropic Cloud

Creatures you control gain deathtouch until end of turn. (Then exile this card. You may cast the creature later from exile.)

Topaz Dragon

Topaz Dragon // Entropic Cloud

Black Dragon

Flying
Acid Breath — When Black Dragon enters, target creature an opponent controls gets -3/-3 until end of turn.

Compelled Duel

Target creature gets +3/+3 until end of turn and must be blocked this turn if able.

Forktail Sweep

Forktail Sweep deals 1 damage to each creature you don't control. (Then exile this card. You may cast the creature later from exile.)

Fang Dragon

Fang Dragon // Forktail Sweep

Red Dragon

Flying
Fire Breath — When Red Dragon enters, it deals 4 damage to each opponent.

Green Dragon

Flying
Poison Breath — When Green Dragon enters, until end of turn, whenever a creature an opponent controls is dealt damage, destroy it.

Bar the Gate

Counter target creature or planeswalker spell. Venture into the dungeon. (Enter the first room or advance to the next room.)

Cave of the Frost Dragon

If you control two or more other lands, Cave of the Frost Dragon enters tapped.
{T}: Add {W}.
{4}{W}: Cave of the Frost Dragon becomes a 3/4 white Dragon creature with flying until end of turn. It's still a land.

Atarka, World Render

Flying, trample
Whenever a Dragon you control attacks, it gains double strike until end of turn.

Temple of the Dragon Queen

As Temple of the Dragon Queen enters, you may reveal a Dragon card from your hand. Temple of the Dragon Queen enters tapped unless you revealed a Dragon card this way or you control a Dragon.
As Temple of the Dragon Queen enters, choose a color.
{T}: Add one mana of the chosen color.

Basilisk Gate

{T}: Add {C}.
{2}, {T}: Target creature gets +X/+X until end of turn, where X is the number of Gates you control. Activate only as a sorcery.

Mountain

Ancient Brass Dragon

Flying
Whenever Ancient Brass Dragon deals combat damage to a player, roll a d20. When you do, put any number of target creature cards with total mana value X or less from graveyards onto the battlefield under your control, where X is the result.

Nautiloid Ship

Flying
When Nautiloid Ship enters, exile target player's graveyard.
Whenever Nautiloid Ship deals combat damage to a player, you may put a creature card exiled with Nautiloid Ship onto the battlefield under your control.
Crew 3

Split the Party

Choose target player. Return half the creatures they control to their owner's hand, rounded up.

Adult Gold Dragon

Sea Gate

Sea Gate enters tapped.
As Sea Gate enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Black Dragon Gate

Black Dragon Gate enters tapped.
As Black Dragon Gate enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Javelin of Lightning

Flash
When Javelin of Lightning enters, attach it to target creature you control.
During your turn, equipped creature gets +2/+0 and has first strike.
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Gate Colossus

This spell costs {1} less to cast for each Gate you control.
Gate Colossus can't be blocked by creatures with power 2 or less.
Whenever a Gate you control enters, you may put Gate Colossus from your graveyard on top of your library.

Oceanus Dragon

Flying
When Oceanus Dragon enters, tap target creature an opponent controls. Goad it. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Ganax, Astral Hunter

Flying
Whenever Ganax, Astral Hunter or another Dragon you control enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Choose a Background (You can have a Background as a second commander.)

Earth Tremor

Earth Tremor deals damage to target creature or planeswalker equal to the number of lands you control.

Arms of Hadar

Creatures target player controls get -2/-2 until end of turn.

Scale Deflection

Put two +1/+1 counters on target creature and untap it. It gains hexproof until end of turn. (Then exile this card. You may cast the creature later from exile.)

Dread Linnorm

Dread Linnorm can't be blocked by creatures with power 3 or less.

Dread Linnorm // Scale Deflection

Ride the Avalanche

The next spell you cast this turn can be cast as though it had flash. When you next cast a spell this turn, put X +1/+1 counters on up to one target creature, where X is the mana value of that spell.

Old Gnawbone

Flying
Whenever a creature you control deals combat damage to a player, create that many Treasure tokens.

Tasha's Hideous Laughter

Each opponent exiles cards from the top of their library until that player has exiled cards with total mana value 20 or more.

Klauth's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Breathe Flame — Klauth's Will deals X damage to each creature without flying.
• Smash Relics — Destroy up to X target artifacts and/or enchantments.

Ancient Den

Blue Dragon

Flying
Lightning Breath — When Blue Dragon enters, until your next turn, target creature an opponent controls gets -3/-0, up to one other target creature gets -2/-0, and up to one other target creature gets -1/-0.

Bhaal's Invoker

Scorching Ray — {8}: Bhaal's Invoker deals 4 damage to each opponent.

Poison the Blade

Target creature gains deathtouch until end of turn.
Draw a card.

Forest

Dragonborn Looter

{1}, {T}: Draw a card, then discard a card.

Magic Missile

This spell can't be countered.
Magic Missile deals 3 damage divided as you choose among one, two, or three targets.

Ancient Gold Dragon

Flying
Whenever Ancient Gold Dragon deals combat damage to a player, roll a d20. You create a number of 1/1 blue Faerie Dragon creature tokens with flying equal to the result.

Ambitious Dragonborn

Ambitious Dragonborn enters with X +1/+1 counters on it, where X is the greatest power among creatures you control and creature cards in your graveyard.